Reclassification of Microseismic Events through Hypocenter Location: Case Study on an Unstable Rock Face in Northern Italy
Passive seismic methods are increasingly used in monitoring unstable rock slopes that are likely to cause rockfalls. Event classification is a basic step in microseismic monitoring. However, the classification of events generated by the propagation of fractures and rockfalls is still uncertain due t...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-01-01
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| Series: | Geosciences |
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| Online Access: | https://www.mdpi.com/2076-3263/11/1/37 |
| _version_ | 1797410948666884096 |
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| author | Zhiyong Zhang Diego Arosio Azadeh Hojat Luigi Zanzi |
| author_facet | Zhiyong Zhang Diego Arosio Azadeh Hojat Luigi Zanzi |
| author_sort | Zhiyong Zhang |
| collection | DOAJ |
| description | Passive seismic methods are increasingly used in monitoring unstable rock slopes that are likely to cause rockfalls. Event classification is a basic step in microseismic monitoring. However, the classification of events generated by the propagation of fractures and rockfalls is still uncertain due to their similar features in the time and frequency domains. Hypocenter localization might be a powerful tool to distinguish events generated by fracture propagation from those caused by rockfalls. In this study, a classification procedure based on hypocenter location was validated using a selected subset of high-quality data recorded by a five-geophone network installed on a steep rock slope in Northern Italy. Considering the complexity and heterogeneity of the rock mass, a 3D velocity model that was derived from a tomographic experiment was used. We performed the localization using the equal differential time method. The location results fairly fit our expectations on suspected rockfall events because most signals were located near the rock face. However, only 4 out of 20 suspected fracture events were unquestionably confirmed as fractures being located inside the rock mass and far enough from the rock face. Further improvements in location accuracy are still necessary to distinguish suspected fracture events located close to the rock face from rockfalls. This study demonstrates that hypocenter location is a promising method to improve the final classification of microseismic events. |
| first_indexed | 2024-03-09T04:37:55Z |
| format | Article |
| id | doaj.art-3e423049ddc44caaad54756d4cce86bd |
| institution | Directory Open Access Journal |
| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-03-09T04:37:55Z |
| publishDate | 2021-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Geosciences |
| spelling | doaj.art-3e423049ddc44caaad54756d4cce86bd2023-12-03T13:25:03ZengMDPI AGGeosciences2076-32632021-01-011113710.3390/geosciences11010037Reclassification of Microseismic Events through Hypocenter Location: Case Study on an Unstable Rock Face in Northern ItalyZhiyong Zhang0Diego Arosio1Azadeh Hojat2Luigi Zanzi3Dipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milan, ItalyDipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via G. Campi 103, 41125 Modena, ItalyDipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milan, ItalyDipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milan, ItalyPassive seismic methods are increasingly used in monitoring unstable rock slopes that are likely to cause rockfalls. Event classification is a basic step in microseismic monitoring. However, the classification of events generated by the propagation of fractures and rockfalls is still uncertain due to their similar features in the time and frequency domains. Hypocenter localization might be a powerful tool to distinguish events generated by fracture propagation from those caused by rockfalls. In this study, a classification procedure based on hypocenter location was validated using a selected subset of high-quality data recorded by a five-geophone network installed on a steep rock slope in Northern Italy. Considering the complexity and heterogeneity of the rock mass, a 3D velocity model that was derived from a tomographic experiment was used. We performed the localization using the equal differential time method. The location results fairly fit our expectations on suspected rockfall events because most signals were located near the rock face. However, only 4 out of 20 suspected fracture events were unquestionably confirmed as fractures being located inside the rock mass and far enough from the rock face. Further improvements in location accuracy are still necessary to distinguish suspected fracture events located close to the rock face from rockfalls. This study demonstrates that hypocenter location is a promising method to improve the final classification of microseismic events.https://www.mdpi.com/2076-3263/11/1/37microseismic event classificationrockfallhypocenter locationmicroseismic monitoringfracture propagation |
| spellingShingle | Zhiyong Zhang Diego Arosio Azadeh Hojat Luigi Zanzi Reclassification of Microseismic Events through Hypocenter Location: Case Study on an Unstable Rock Face in Northern Italy Geosciences microseismic event classification rockfall hypocenter location microseismic monitoring fracture propagation |
| title | Reclassification of Microseismic Events through Hypocenter Location: Case Study on an Unstable Rock Face in Northern Italy |
| title_full | Reclassification of Microseismic Events through Hypocenter Location: Case Study on an Unstable Rock Face in Northern Italy |
| title_fullStr | Reclassification of Microseismic Events through Hypocenter Location: Case Study on an Unstable Rock Face in Northern Italy |
| title_full_unstemmed | Reclassification of Microseismic Events through Hypocenter Location: Case Study on an Unstable Rock Face in Northern Italy |
| title_short | Reclassification of Microseismic Events through Hypocenter Location: Case Study on an Unstable Rock Face in Northern Italy |
| title_sort | reclassification of microseismic events through hypocenter location case study on an unstable rock face in northern italy |
| topic | microseismic event classification rockfall hypocenter location microseismic monitoring fracture propagation |
| url | https://www.mdpi.com/2076-3263/11/1/37 |
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